This invention relates to pipe couplings and more specifically to a novel and useful pipe coupling which is particularly suited for joining unthreaded pipe sections of the PVC type.
It is a primary object of the invention to provide a pipe coupling which, as a result of its unique design, is capable of joining the open ends of heavy gauge PVC pipe sections while maintaining the longitudinal axis of both sections parallel to each other at all times. This feature is particularly useful when the open ends of the pipe sections to be joined are spaced apart and fixed on a common longitudinal axis such as when they extend between walls of a building or are buried in the ground and it is desired to connect the ends by means of an intermediate section. Further when the pipe sections are of the thick walled, PVC (polyvinyl chloride) type they are substantially incapable of being bent particularly when the location of the point where they are fixed is proximate the end thereof to be joined. In addition applicant's coupling is designed so that when the coupling has been correctly installed, i.e. the pipe ends being joined are at the midpoint of the coupling, the relative position of the coupling elements with respect to each other give a visual indication that the pipe ends are at the midpoint of the coupling.
The prior art structure in this area of which applicant is aware is exemplified, for example, in U.S. Pat. No. 3,857,588 which discloses a coupling for pipes of the PVC type which consists of two or more elements which are bonded by solvent cement to the pipe sections and to each other. However, it is necessary to bend at least one of the pipe sections before the coupling can be installed which presents little problem when the pipe is of small diameter and of relatively thin wall construction. However, when the pipe sections to be joined are of large diameter, thick wall construction and are fixed relative to each other, they cannot for all practical purposes be bent sufficiently to install the aforementioned pipe couplings of the prior art.
In addition numerous other pipe couplings for PVC type pipe have uninterrupted internal surfaces which make it difficult to determine exactly at what point in the coupling the pipe ends are joined.
It is therefore a further primary object of the present invention to provide a superior coupling for pipes of the unthreaded PVC type.
It is another object of the present invention to provide a coupling which, due to its unique construction is particularly suitable for joining open ended, rigidly fixed, thick wall spaced apart sections by means of an intermediate section of pipe without any degree of bending either pipe section.
It is yet another object of the present invention to provide a coupling which, due to its unique construction, permits a visual indication that the coupling has been correctly installed as required by the plumbing codes in numerous jurisdictions.
It is a further object of the present invention to provide a pipe coupling of the type described which is easily and quickly installed due to its tapered inner surfaces, which is inexpensive to manufacture, and which in one embodiment thereof has an additional sealing means.
These and other objects of the invention will become apparent during the course of the following description and appended claims, taken in connection with the accompanying drawing forming a part hereof.